He has an excellent point about law enforcement officials accessing private property without permission or a warrant.
And, while I don’t think a law forbidding it is necessary, it does not strike me as a particularly good idea to ride an ATV with a loaded crossbow... ...at least not the way I ride ATVs. ;-)
--as far as the game warden on "private property" , while I can't speak to Illinois, many states have some variation on the "open fields" law (as it is called in South Dakota) --a law enforcement officer can patrol on farm or ranchland but would need a warrant to enter a building, except in cases of pursuit or "probable cause", if suspecting a felony was in progress------